Apparatus for progressively heating oil sands surrounding oil wells



y '6, 148 R. M. STEFFEN 2,444,756 APPARATUS FOR PROGRESSIVELY HEATINGOIL SANDS SURROUNDING OIL WELLS I 4 Filed Jan.

Patented July 6, 1948 APPARATUS FOR PROGRESSIVELY HEAT- SURROUNDING OILIN G OIL SANDS WELLS Ralph M. Steffen, North Hollywood, Calif., assignorto National Secondary Recovery Corporation, Reno, Nevada, a

corporation of Nevada Application January 4, 1946, Serial No. 639,126

6 Claims. (Cl. 16617)" This invention relates to. apparatus forprogressively heating oil sands surrounding an oil well.

The primary object of this invention is to provide a novel apparatus foraugmenting the yield from oil wells. 1.

An important object of the invention is the provision of apparatus whichis applicable to existing wells to renew or increase this output, orwhich may be employed with equal facility in low yield shale and oil.sands and in fields where normal procedures for development of the .oildeposits are not practicable.

A further important object of the invention is the development ofapparatus which shall concurrently condition the oil strata forincreased oil flow and effect an increased output from the well.

A still further important object of the invention is the provision of animproved apparatus for efiiciently heating the oil bearing sands from ian immersion type heater which may be adjustably positioned in a Well.

An additional object of the invention is the provision of an apparatusfor heating the bottom portion of an oil well provided with a perforatedcasing and with an oi1 pump whereby the surrounding oil sands areprogressively heated radially of the well for facilitating flow of oilfrom the sands into the Well.

A further object of the invention is the provision of an apparatus forheating the oil sands surrounding an oil well having a perforated casingand an oil pump therein by the ignition of successive charges ofcombustible gas confined within a tubular heating coil surrounding thepump tubing, whereby heat is radiated from the walls of the coil and istransmitted through the casing and perforations into the surrounding oilsand for progressively heating in successive zones radially of the wellfor facilitating flow of oil from the sands to the well aswell as toadjoining wells.

A still .further object of the invention is the provision of arelatively simple and effective apparatus for carrying. the method intoeifect.

With the above recited and other objects in view, the invention is setforth in thefollowing specification and illustrated in the accompanyingdrawing, wherein Fig. 1 is a vertical sectional view coaxially of a welland illustrating successive zones of oil sand in surrounding relation tothe well;

Fig. 2 is a transverse sectional view substantially in the plane of line22, Fig. l.

Referring now in detail to the drawing, the numeral Ill designates awell casing which may be provided with perforations II in the lower endportion thereof. A pump delivery tubing I2 is disposed within the wellcasing I0 coaxially thereof and near its lower end may be provided witha flanged collar, such as indicated at I 3. The pump tubing at its upperexposed end is provided with an oil delivery conduit. I 4 provided witha valve I5. A pump sucker rod I6 extends downwardly within the tubingI2, and at its lower end is connected with the pump I1, and at its upperend is connected with the pump jack I8. By this mechanism, oil is pumpedfrom the bottom of the well, as in usual practice. It frequently occurs,however, that when a well ceases flowing, after pumping, that therestill remains a residuum of oil in the strata, which, owing to itsviscosity or the temperature of the strata has not heretofore beenprofitably recoverable. If, however, this strata can be effectivelytreated with heat, considerable oil can be induced to flow into the welland be reclaimed.

This important desideratum is effected by the novel heating device nowto be set forth.

In accordance with the present invention, a tubular coil I9 surroundsthe pump tubing I2 below the flange I3 and is supported thereon, and asillustrated the diameter of the coil is suchas to enable it to belowered into the well and over the flange I3. The coil is preferablydouble or one which extends downwardly from the flange I3 andthenceupwardly to the flange. This arrangement not only avoids terminating thecoil below the maximum oil level in the well, but of more importanceprovides a greater heat radiating surface on the coil.

The coil as formed has two upper ends, one of which terminates above themaximum oil level in the form of a gooseneck I9. To the other end of thecoil is suitably secured the lower end of a tube or conduit 20 which isextended at its upper end along the ground surface, preferably by theprovision of additional conduit lengths. The conduit 20 above the wellis provided with f ."ergized'so asto produce a check valve 2|, and isfurther provided with a spark plug 22, energized by an ignition circuit,not shown, between the check valve and the top of easing Ill.

In assembly, the coil 19 is lowered into the well by means of conduit 20which in practice is constructed of readily attached successivesections, thus facilitating the positioning of the coil. It will be herenoted that the flange and coil may be progressively lowered or raised inthe welltin'nonformity "with archanging'oil level. The coilis. suspendedin the well in surrounding relation to the pump tubing 12 and from theflange 13. The tubing from which the coil "I 9 is formed is preferablyabout .twodnehesdnadiameter, while the diameter of tube qorz-conduitizflis about one-half inch in diameter, for the pur pose later to appear.

In operation of the structurejdisclosediincarrying the heating methodinto reflect, 'a--combustible gas is admitted through the check valve 2|into conduit extending. downwardlyiwithin the casing Ill and thence intothe coil l9. When a combustible chargehas filled the coil substantially,to the end I9 thereof, the plug 22 is en a spark and the charge thusignited. q H

The burninggase'swithin the-coil l9 heat-the tube wallsjthereof and theheat-radiated therefrom travels through the surrounding oil mediumandithence through-casing l0 and into the oil -sand, asindicated 1 bythe arrows having'open fiheads, and as identified in the legend on thedrawing. tThegas' is admitted tothe coil and igllitd about'ten;times perminute with the re- .Lsult that. heat is continuously generated andradiatedfromthecoil. As a resu1t,'the zone of the oil sandjlindicated as.Awill become heated and .the heat;will progressively penetrate thezones "B and C .whereby the oil sands will become iheated'fonasubstantial'distance from the'well, and oil-will; thus be caused'toflowtherefromto- "wardend intothe well, ,as' is indicated by the.;arrows -having solid heads. Furthermore, this ,progressive heating ofthe oil sands will-result ;in stimulating and-facilitating "the flow "ofoil fin'thefield. as a whole to adjacent wells.

While'the zones A, Band-C are indicated as distinct,;.such is forpurpose of explanation only,

asthere is of course no clear line of demarcation between" the.successive zones referred to.

As before. stated, the relatively large tube diameterof the coilprovides a desirablylargeheat radiating surface, while the substantiallySmaller tubeifi, due to its relativesmallsurface; is rapidly .cooledby'thegas entering prior to ignition thereof, 'ther'ebyavoiding anotherwise overheated condition 'occasioning 'pre-ig-nition and "damageftherfrom. The operation as abovedescr'ibed maybe continuoussince .theplug 22,.may be energizedat regular timed.intervals'.by any suitable:control ..means, and the check valve 2| will admit gas gprior toignition and .will restrict the-flow immediately .following ignition dueto increased pressure in tube zfl'andcoil l9. Upon-reduction of pressurewithin the, coilafterthe ignition, combustible gas will again beadmitted through valveZi which will drive the" burned hotygases'outthrough the open end l9f of-thecoil thereby 'f-urtherheating thewell and'oil sand.

.It shouldbeunderstood here that I-contemplate availing myself "of avariety (if-instrumen- "ztalitiesfm effecting this operation. 'Thecom-*bustible mixturemay be supplied under any desirable pressure, it beingevident that I may vary the same during the operation to meet varyinglocal conditions. Further, the top of the well casing may be enclosed,with a controllable vent, whereby a back pressure may be maintained, incertain instances, in the casing and coil, with beneficial influenceupon the rate and extent of heat propagation through the concentriczones A, B and C. By reason of the unidirectional flow of the fuelmixture, more even heating and bettersoavenging of theheatingtelementfis'obtained, which are-important advantages,particularly in view Of the frequent extreme depths at which pumping isoften required.

:Itriseto-tbeeparticularly observed that the coil "-l'filisofiaiiengthtto traverse a substantial depth of the sandrand-rdue to itsduplex form, a substantially large heat radiating surface is provided.

=Whil-e?l:havefdisclosed the invention in accordance "with "a singlespecific embodiment thereof; the same'is to be considered asillustrafiYGEDIY,-2&Hdiflr0t restrictive, the scope of the inventionbeing defined in the sub-joined claims.

1. Apparatus for progressively heating successive-zonesofoil'sand-'ra'dially of -a=well having a perforated casing and-a pumpsupported therein by a tubing extending axially of the well-to a pointexteriorly-theredf, =comprising a tubular -coil surrounding the pumptubing, aconduitconnected with an end of the coil and extendingupwardlythrough the well'and externally thereof "to point of combustiblegas supply, a check "valve in the -'conduit fonadm-itting successivechargesof -combustible-gas to the coil and=means 'fordgriitingtheflsuccessive gas'charges whereby *the'coilwall isheated and the heatradiated therefrom through the -'casing perforations and intothe'surroundingoilsand; said coil being suspended 'from a flange on -thepump tubing, the inner diameter "of said cell being greater than thediameter of theilange' to facilitate admission of the coil over thetubing and into the well. f2. Apparatus"for progressively'heat-ingsuccessive zones of ofl san'd radially of 'a we'llhaving "a perforated"casing and -a pump supported therein'by atubing-extending axiallyof thewell to a point exteriorly thereof; comprising atubular-coil-surrounding the pump tubing, a-conduit *connctedwith an endof the-coil and extending upwardly through thewell and externallythereof toa-point of 'combu'stible'gas supply, a check valve in theconduit for admitting successive charges'of combustible gas to thecoil'and means for igniting the successive'gas chargeswhereby "the coilwall isheated and" the heat radiated "therefromwhrough the casingperforations and "into the surrounding oil sand, the coil tube be-"ing'of relatively larger diameter'and the conduitofrelativelysmaller-diameter.

3. *Apparatus for heating'the oil-sand strata radially of 'an'oil --wellI having a pump supported {therein by a tubing extending axially of "thewell "to "an exterior point, comprising; a 5 supporting"member-on-said"tubing,"a tubular coil surrounding 'the'tubing andcarried'bysaid supporting merfrber, a conduit connected with said-coiland extending ext-eriorly of said well to a source'of "combustible gas;a valvein said conduit for admittingsuccessive charges of combustiblegas to the-coil, and-means for ignitingthe'successive gas "charges 'forheating said coil and thereby 'the'surroundingroilsand strata.

4.*The pom-binationof -claim 3 "wherein "said conduit is of lesscross-sectionalarea thansaid RALPH M. STEFFEN.

6 REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date Harris Feb. 19, 1878 Elten Apr.26, 1910 Breitung et a1. Sept. 7, 1915 Drinkern July 15, 1919 KreagerMay 3, 1927 Hixon Sept. 19, 1939 Pick Dec. 7, 1943

